直接Z型Zn2SnO4-xNx/ZnO1-yNy异质结光催化剂的制备及机理 |
Synthesis and Mechanism of Direct Z-Scheme Zn2SnO4-xNx/ZnO1-yNy Heterojunction Photocatalyst |
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摘要: 采用微波溶剂热法成功制备直接Z型Zn2SnO4-xNx/ZnO1-yNy核壳结构异质结光催化剂。2种物质不同的功函数改变了其表面电荷密度,并在界面处形成内建电场,导致其从传统的Ⅰ型镶嵌异质结转变为Ⅱ型异质结,再转变为Z型异质结构。N杂质原子替代O原子进入Zn2SnO4和ZnO的晶格,在两者的价带(VB)顶部形成双杂质能级。核壳结构的Z型异质结光催化剂对罗丹明B的降解速率为纯相Zn2SnO4-xNx的1.40~1.43倍,同时具有良好的循环稳定性,且可以降解亚甲基蓝、甲基橙、水杨酸等污染物。Z型异质结的形成使其光生电子-空穴对具有较强的氧化还原能力,而双杂质能级的存在可以拓宽其光响应范围并提高载流子的分离效率。因此,Zn2SnO4-xNx/ZnO1-yNy异质结光催化剂高的光催化活性归因于Z型异质结和双杂质能级的协同作用。 |
关键词: 光催化 氮掺杂 Z型 Zn2SnO4-xNx ZnO1-yNy |
基金项目: 国家自然科学基金(No.51772180)、科技部重大研究项目(No.2017YFC0210803)和陕西科技大学研究生创新基金(No.SUST-A04)资助项目。 |
Abstract: The direct Z-scheme Zn2SnO4-xNx/ZnO1-yNy heterojunction photocatalyst was successfully prepared via a microwave-assisted solvothermal method. N atoms were introduced in to the lattices of Zn2SnO4 and ZnO by replacing O atoms to form Zn2SnO4-xNx and ZnO1-yNy units, resulting in the formation of N impurity levels at the top of valence band (VB). The transformation from Ⅰ-type to Ⅱ-type, and then to Z-scheme heterojunction of Zn2SnO4-xNx/ZnO1-yNy was attributed to the rearrangement of interface charge distribution induced by the different work functions and the construction of build-in electron field. The photocatalytic activity of heterojunction photocatalyst was evaluated by the photo-degradation of RhB under UV light irradiation. The degradation rate of RhB over Zn2SnO4-xNx/ZnO1-yNy heterojunction photocatalyst was 1.40~1.43 times higher than that of two pure Zn2SnO4-xNx samples. Methylene blue, methyl orange and salicylic acid could be degraded over Zn2SnO4-xNx/ZnO1-yNy heterojunction photocatalyst, which also exhibited good cyclic stability. The high photocatalytic activity of Zn2SnO4-xNx/ZnO1-yNy heterojunction photocatalyst was ascribed to the synergistic effects between Z-scheme heterojunction and double impurity levels due to the enhanced redox ability and improved separation efficiency of photoinduced charge carriers. |
Keywords: photocatalysis nitrogen doping Z-scheme Zn2SnO4-xNx ZnO1-yNy |
投稿时间:2019-03-17 修订日期:2019-05-21 |
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王敏,谈国强,张丹,李斌,王颖,党明月,任慧君,夏傲,刘运.直接Z型Zn2SnO4-xNx/ZnO1-yNy异质结光催化剂的制备及机理[J].无机化学学报,2019,35(9):1551-1560. |
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